The present invention relates to a packaging installation for forming finished products such as packs from batches of articles.
The present invention notably applies to the packaging of articles such as bottles or cans, generally cylindrical in shape.
It is known that the articles are first of all routed individually on a supply track up to a grouping station where batches of articles are formed and then spaced apart in order to be transferred to a discharge track, along which they are wrapped, or packed.
In order to form a space between two successive batches of articles, it is known that the batches of articles can be accelerated between the supply track and the discharge track.
The document GB-974 995 can notably be cited.
The space then formed between the same faces of two consecutive batches is referred to as the xe2x80x9cpitchxe2x80x9d or xe2x80x9cmachine pitchxe2x80x9d.
Because of the preservation of the throughput of the machine, it is easy to establish, between the linear output speed of an article and its input speed, the following relationship:   VS  =      VE    xc3x97          P      L      
where VS is the output speed of the article, VE its input speed, P the machine pitch and L the length of a batch of articles.
Distributors are at the present time seeking to reduce their stocks whilst offering every more diversified ranges of packaged products.
As a result the throughput of the packaging machines must be continually upgraded. Thus, in the field of the packaging of bottles or cans, at the present time throughputs of around 15,000 to 100,000 bottles per hour are currently being achieved.
In addition, distributors require to be able to vary their offer within the same product range, offering to consumers, for the same articles such as a bottle or a can filled with a beverage, varied packagings such as packs of two, three, four, six or eight articles or more.
In order to meet these requirements, manufacturers must be in a position to continually renew their machine ranges, so as to adapt them not only to the shapes of new products, to their sizes, to their weights, but also to the size and shape of their packaging, usually cardboard blanks or equivalent.
At the present time, manufacturers are offering distributors packaging solutions or machines which have many drawbacks.
Certain manufacturers are offering distributors one machine for each type of finished product, which is cumbersome and expensive.
Other manufacturers, for their part, are offering one machine for each range of products, which requires setting the machine according to the type of packaging required: batches of two, four, six, eight or more.
This is because, for a constant machine throughput (and therefore a constant input speed), it is necessary to adapt the output speed and/or the machine pitch, through the equation given above.
The majority of machines do not have a pitch adjusting system. It is therefore necessary to increase the output speed, the pitch being fixed whatever the number of articles per batch.
Thus, changing for example from a grouping by batches of twelve articles to a grouping by batches of four makes it necessary to triple the output speed of the machine, which is incompatible with the physical limits of the installations, and in particular the packaging devices.
Some machines have manual pitch adjusting systems, which requires as many manual actions as there are changes of product within the same range.
At the present time, the frequencies of these changes may attain two to three per day, a frequency which is difficult to achieve by means of manual adjustments.
The invention aims at resolving notably the aforementioned drawbacks of the prior art, by proposing an installation which allows the automatic adjustment both of the number of articles per batch, of the machine pitch, and of the production rate.
To this end, the object of the invention is a packaging installation for forming finished products, such as packs, from batches of articles, which comprises:
a conveyer able to receive the successive batches of articles in order to route them from a so-called upstream location to a so-called downstream location, the upstream faces of two successive batches being spaced apart by a predetermined distance known as the pitch;
a feed track along which the articles are routed one by one to the said conveyer whilst being juxtaposed with each other;
means of transferring the articles from the feed track to the conveyer, able to take and group the articles in order to form batches spaced apart;
a transporter able on the one hand to route cardboard blanks or equivalent one by one, placed substantially flat on the transporter, to the said conveyer, and to dispose the blanks on the conveyer opposite batches of articles;
means of driving the conveyer, the transfer means and the transporter.
The installation is characterised in that it comprises a control and slaving device for the drive means, able to apply to each drive means a speed profile chosen from amongst a preprogrammed set of speed profiles, to allow the adjustment of the pitch and/or of the number of articles per batch according to the pitch and/or the type of batch required.
To each type of packaging there corresponds a speed profile for each of the drive means.
By programming these speed profiles in advance, it is therefore possible to change automatically from one to another, so that setting the machine is easy and rapid.
It is thus possible to change immediately from one type of packaging to another, for example from a packaging by batches of eight to a packaging by batches of four, whilst maintaining the output speed constant.
According to one embodiment, this installation also comprises:
means adjacent to the feed track and to the transfer means, able to sequence and time the articles coming from the feed track so that they have the required positioning and separation at the time they are gripped by the transfer means; and
a means of driving the means for sequencing and timing the articles, slaved to the control device.
According to one embodiment, the said transfer means comprise a toothed wheel, at least part of which is mounted so as to pivot about a rotation shaft, this wheel being disposed close to the supply track and the discharge track, substantially tangent to these, this wheel comprising the so-called gripping members.
The gripping members are for example in the form of teeth substantially regularly spaced apart, projecting radially from the toothed wheel, each tooth describing a circle passing through a first angular position in which it engages at least one article at the supply station, and a second angular position in which it disengages it at the discharge station.
According to one embodiment, the wheel comprises a circular fixed base and a rotating disc, coaxial in place one above the other, between which are disposed radial arms whose free ends form the said teeth.
According to a particular constructional arrangement, the said arms are mounted for rotation on the disc by means of pivots with axes parallel to the axis of the wheel.
For example, each arm has a roller or toe which cooperates with a groove formed in the base, this groove being extended in a closed loop around the axis of rotation of the wheel.
This groove is arranged so that:
when the tooth passes through the supply station, the arm which carries it pivots in the direction opposite the rotation of the wheel so that the speed of the wheel decreases until it is substantially equal to the input speed when the articles are engaged;
between the supply station and the discharge station, the orientation of the said arm is constant with respect to the wheel so that the speed of the tooth increases until it is substantially equal to the speed of the wheel, so that the articles are grouped together in batches, accelerated and spaced apart.
There can also be provided means disposed close to the supply station, able to sequence and time the articles coming from the supply track, so that they have the required positioning and separation at the time they are gripped by the transfer means.
According to one embodiment, the said transporter comprises pushers for the blanks arranged successively on the transporter, each pusher being able to come into engagement with a blank in order to route it to the conveyer, the distance between two successive pushers in engagement with a blank being predetermined and substantially equal to the pitch.
It is also possible to provide:
means of adjusting the distance between two successive pushers in engagement with a blank in accordance with a predetermined value chosen from amongst a group of preprogrammed values, all multiples of the same value known as the modulus;
a means of driving the adjustment means, slaved to the control device.
According to one embodiment, the control device is arranged to apply to at least one of the drive means, and for example to each drive means, a predetermined speed profile, chosen from amongst a preprogrammed set of speed profiles.
To this end, the or each drive means can comprise a motor whose speed of rotation is continuously adjustable, such as an electric motor, of the brushless DC type.